Lag and broken highlights when playing 4K HDR file through Jellyfin Media Player

[Caption2457]

I'm not sure where exactly does the problem lay, so I'll will explain the situation as detailed as possible, in hope that someone will have some clue.

I am trying to play a 4K HDR HEVC file through the desktop client (on a laptop with non HDR monitor). No transcoding is being used, just direct playback (verified).

I've read that Jellyfin Media Player is using MPV, so I put a mpv.conf file with the parameters that I'm using with my MPV player. (I verified that the config file is being read)
My config parameters:

hwdec=vaapi
vo=gpu-next
hdr-compute-peak=no
tone-mapping=mobius
target-peak=100

I've noticed the following problems: The playback is laggy and there is something wrong with the highlights (maybe related, maybe not). The exact same problems can be observed both on Linux and Windows. (The lag is also there, maybe even worse, without changing any configs)

MPV / Jellyfin MPV shim
     

Jellyfin Media Player (the same mpv.conf)
   

There is nothing wrong with the hardware as I tried streaming the file through jellyfin mpv shim and the playback is behaving the same way as being played locally with mpv. (smooth playback, no problem with highlights)

My only idea is that maybe there are some other configs that are interfering?

[TheDreadPirate]

I'm not sure that JMP utilizes your mpv.conf. While it uses MPV as the player, there are additional shenanigans going on with how JMP utilizes MPV.

The consensus is that JMP does not do HDR well/at all. Not sure which. And that MPV Shim should be used for HDR content.

[Caption2457]

I'm not sure that JMP utilizes your mpv.conf.  While it uses MPV as the player, there are additional shenanigans going on with how JMP utilizes MPV.

The consensus is that JMP does not do HDR well/at all.  Not sure which.  And that MPV Shim should be used for HDR content.

It is utilized, as changes is target-peak are visible. But if that is the case and JMP doesn't work well with HDR, I won't bother trying to fix it 😅.
Thanks for the reply!